Organized by the World Wide Fund for Nature (WWF), Earth Hour takes place every March on a day selected by the organization. Participants, which include cities, individuals, and famous landmarks such as the Eiffel Tower, turn off their lights between 8:30 and 9:30 p.m. local time to demonstrate the importance of saving energy and conserving resources.

"Earth Hour reminds us that while people are on the front lines of climate change, they are also our first line of defense,” said Earth Hour global director Siddarth Das this week. “Our actions today, as individuals and the global community, have the power to transform what the world will look like for generations to come."

More than 350 world landmarks in 178 countries are scheduled to take place in Earth Hour this year. This year's theme is “Places We Love,” a reminder that unchecked climate change threatens to destroy beloved natural places such as beaches and mountains.

Event organizers say that this year’s Earth Hour is particularly important because of the recent Paris agreement on climate change, which includes worldwide efforts to reduce carbon emissions and spread green technology.

But the unprecedented Paris treaties raise the question: With so much of the world taking action on climate change, do we still need to raise awareness?

In 2007, Earth Hour began in Australia. The next year, it emerged as a worldwide event, and at the time climate change was considered less of a global certainty than it is today, although the scientific community has warned about global warming since at least the 1970s. Only 35 countries participated in the first worldwide Earth Hour.

The next year, the United Nations hosted a conference on climate change in Copenhagen which failed to produce international accord. Some say that the world’s most developed nations, including the United States, were to blame.

As of 2010, a Pew study found that while only 37 percent of Americans and 40 percent of United Kingdom residents saw climate change as a very serious problem, 85 percent of Brazilians and 58 percent of Japanese citizens expressed deep concern. That same year, the number of countries participating in Earth Hour rose to 128.

Two years earlier, a European Commission study found that 62 percent of Europeans saw climate change as a serious problem, making it the second most significant problem the world faced. By 2011, another study ordered by the European Commission found that 89 percent of European survey respondents believed climate change to be a "serious" problem, including 51 percent who called it a "very serious" problem.

More recent data tells a slightly different story. According to a worldwide Pew survey conducted in 2015, between 50 and 60 percent of Europeans on average saw climate change as a serious problem.

According to the same Pew survey, 45 percent of Asians and 38 percent of Middle Easterners saw climate change as a significant problem.

A separate Pew survey, released in advance of the Paris talks, found that citizens of the United States and China lagged behind people from many other nations in seeing climate change as a serious issue that has the potential to affect them.

Other researchers have looked at the prevalence of "climate change deniers," individuals who insist either that climate change is not happening or that it is not caused by humans. A 2014 survey conducted by Ipsos Mori found that among survey respondents worldwide, the United States had the greatest percentage of climate change deniers. The United Kingdom and Australia also had fairly high denial rates.

Republican politicians in particular continue to deny climate change. Last fall, for example, Republican presidential candidate Ted Cruz said, “Climate change is not science. It’s religion," and in 2012, Oklahoma Sen. James Inhofe (R) published The Greatest Hoax, a book about climate change. As of January 2015, just 15 percent of US Republicans saw climate change as a priority for the government, compared to 54 percent of Democrats.

As Pew researchers wrote, “Democrats are much more likely than Republicans to see climate change as a problem, to believe its effects are being felt now, to think it will harm them personally, and to support U.S. participation in an agreement to limit greenhouse gas emissions.”

While government officials from most of the world's nations have agreed to take steps to curb climate change – and the majority of Americans now agree that climate change has a man-made component – the lingering influence of climate change deniers suggests that Earth Hour remains relevant.

“The world is at a climate crossroads,” Earth Hour's Mr. Das. “While we are experiencing the impacts of climate change more than ever, we are also witnessing a new momentum in climate action transcending borders and generations. From living rooms to classrooms and conference rooms, people are demanding climate action. This tenth edition of Earth Hour is our time to ensure people are empowered to be a part of climate solutions.”